Present cable TV systems generally transmit off the air television broadcasts or other programs to subscribers who pay for the privilege of receiving the programs. Within this field, there has long been a need for a cost-effective method of controlling access to the cable system. At the present time, particularly in a dedicated system where taps for connecting subscribers to the system are installed during initial construction, a technician is sent to a subscriber location and utilizes a lift-truck while either connecting a subscriber's lead-in cable to a tap port, or disconnecting the subscriber's cable from the port. It is obvious that a method for providing such an action from a central office or control center would save considerable time and money, and also improve the flexibility of the system generally. A suitable remote control system would permit not only control of a subscriber's access to the system as a whole, but might also allow for partial access to the system on a time basis, an individual channel basis, or both. Thus, a subscriber might be permitted to view none, one, several or all of the available channels of programming. Furthermore, the subscriber might be permitted to view one or more specific channels only at specific times depending upon the terms of his subscription.
In addition to the advantages such a system can provide for the control of basic services, it would be of even greater advantage in the control of pay-TV services. For example, in some pay television systems contemplated by the present art, it is proposed that coin boxes or other receptacles suitable for receiving payment from a subscriber for viewing a particular television program be installed on the subscriber's television receiver. Upon deposit by the subscriber of required payment into the payment receptacle, a switch located adjacent the receptacle or television receiver would be actuated whereby viewing of the desired program would be permitted. In order for the sponsor of the pay TV service to collect its revenues it, too, would be required to dispatch an individual to the subscriber's location to empty the payment receptacle. Enterprising subscribers may, through the use of jumper wires, be able to bypass the payment receptacle in order to view the desired program without making the required payment. Bypass is also possible where purchased tickets or other buying means are needed to actuate the subscription channels.
It would be desirable to avoid these difficulties by permitting the system management to provide or deny pay-TV or special channel services on a remote control basis. Remote control of the provision of pay-TV service on one or more channels would also be desirable to permit a multilevel operation of these channels. As an example, it would be useful to provide that a channel dedicated to pay-TV could be sold at one level of programming (i.e., fee) in the morning, at a second level at midday, and a third level in the evening, and to allow the system operator at the program center to turn on or turn off subscribers who are buying or not buying that particular level of service. In addition access to individual programs could be controlled.
Still another remote control operation that is desirable, among others, is the remote energizing of a transponder device which may very well take signals from a store which serves as a memory for actions in the subscriber location, in a section of the cable system, in a nearby amplifier or in a host of other potential locations where remote status indication is of importance.
One approach to remote control of a subscriber location has been in essence to provide a duplicate of an RF paging system, requiring transmission of special control signals below 300 khz transmitted in addition to programs and power, but with some switches in place of the conventional "beeper" or tone oscillator plus speaker. This is a complex system and extremely expensive to implement, particularly for use in an outdoor environment. The provision, installation and operation of the many required RF receivers makes this system fail to meet the need for a cost-effective remote control cable TV network.